The present invention relates generally to controlling pressure in disk drives.
One way to increase the data transfer rate of magnetic disk drives is to increase the revolutions per minute (rpm) at which the disk drives operate. Increasing the operating rpm, however, increases the power consumption of disk drives. In order to decrease the power consumption, the disk drive can be evacuated to reduce the air pressure therein and, hence, reduce frictional losses. Unfortunately, if the air pressure within the drive is reduced too much, the read/write head may contact the surface of the storage disk, causing errors or even failure of the drive. Accordingly, the present invention recognizes that the air pressure within the drive must be established to avoid head contact with the disk while minimizing the power consumption of the drive.
The present invention further understands that to provide for disk drive pressure control, a dedicated pressure sensor may be included in the drive components. The additional part, however, increases the manufacturing time and production costs. Therefore, in light of the above problems, the present invention recognizes a need for a method to control the pressure within an evacuated disk drive that does not necessarily require, e.g. a dedicated pressure sensor.
A disk drive controller includes logic for establishing pressure within a disk drive housing. The logic includes receiving a signal representative of a disk drive spindle power. The signal is used to establish pressure within the housing.
Preferably, the logic compares the signal representative of the disk drive spindle power to a predetermined power value. The comparison is used to establish pressure within the housing. In a preferred embodiment, the logic also receives a signal representative of a fly height and then uses the fly height signal to establish the air pressure within the housing. Preferably, the logic determines a minimum fly height value and then compares the signal representative of the fly height to the minimum fly height value. This comparison is also used to establish the air pressure within the housing. The logic also compares the signal representative of the fly height to a predetermined maximum fly height value to further establish pressure within the housing at least partially based thereon.
In a preferred embodiment, the method acts embodies by the logic further include determining a reference value for a parameter with the read/write head in the parked position, either on the ramp of the drive or in the contact start-stop zone of a CSS drive, and a loaded value for the parameter. Then, the calibration value for the fly height is determined based on a comparison of the reference and loaded values for the parameter.
In another aspect of the present invention, a method is provided for establishing pressure in a disk drive housing that includes a disk drive and communicates with a pump. In this aspect of the present invention, the method includes receiving at least one non-pressure electrical signal from the disk drive, and then controlling the pump in response to the signal.
In yet another aspect of the present invention, a disk drive assembly includes a disk drive housing and a disk drive within the housing. A pump communicates with the disk drive housing. Moreover, the disk drive assembly includes a controller that receives at least one electrical signal that represents an operating power in the disk drive. The controller controls the pump in response to the signal.